When to plant cucumbers in Grand Junction: 6 May – 12 August

In Grand Junction, cucumber: sow for seedlings from 18 March to 15 July; plant into a greenhouse from 15 April to 12 August; plant out into open ground from 6 May to 12 August. For plants and seeds, the places nearby include West Elk Supply (farm supply, 2 km) and Bookcliff Gardens (garden centre, 3 km); addresses and opening hours are below.

Cucumber in Grand Junction: soil, season and weather

In Grand Junction the soil, not frost, sets the date: the last frost is over around 18 April, but the top 7 cm of soil reaches 18 °C — the minimum on the cucumber card — only around 6 May, 18 days later.

Last spring frost	18 April
Top 7 cm of soil at 18 °C	6 May, 18 days after the last frost
Into an unheated greenhouse	15 April – 12 August; April outside: 4.6 °C at night, 19.9 °C by day; card 18–25 °C
First autumn frost	27 October, 174 days after the start
Days in the bed to the first harvest (card)	34
First harvest, if planted in this window	9 June – 15 September
Days left for picking	140
Daylight	12:55 on 8 April, 14:00 on 6 May
Watering outdoors when fruiting (card)	every 2 days; the driest month, June, has 3 rainy days

The same dates in Grand Junction hold for Bell Pepper, Eggplant, Zucchini, Pumpkin and Watermelon.

Cucumber in Grand Junction: care after planting

Planted on 6 May: in the first weeks water every 4 days.

Feeding, by the card’s schedule from that day:

13 May — feed: nitrogen

Pests and diseases of cucumber to watch for:

Dates count from the first planting day of the window above; a later planting moves them by as many days.

Weather in Grand Junction during the cucumber season

Days average above the cucumber card's 18–35 °C in July (35.1 °C). Nights average below 18 °C in May, June and September, October (6.1–16.4 °C).

Month	Day, °C	Night, °C	Rain, mm	Rainy days	Daylight on the 15th
May	25.4	9.7	30	6	14:18
June	32.8	16.4	13	3	14:54
July	35.1	19.8	15	2	14:40
August	33.3	18.3	24	5	13:44
September	28.9	13.8	28	5	12:29
October	19.6	6.1	54	7	11:14

ERA5 2016–2025, Open-Meteo

Cucumber in nearby cities

Around Grand Junction, Pueblo is 3 days earlier and Cheyenne 33 days later.

City	Distance	Date	Difference
Denver	316 km	28 May – 31 July	22 days later
Colorado Springs	326 km	6 June – 31 July	31 days later
Salt Lake City	339 km	19 May – 11 August	13 days later
Fort Collins	340 km	7 June – 6 August	32 days later
Pueblo	356 km	3 May – 13 August	3 days earlier
Cheyenne	392 km	8 June – 29 July	33 days later

Where to buy cucumber plants and seeds near Grand Junction

Buy plants ready to set out from 6 May to 12 August (from 15 April to 12 August for an unheated greenhouse); seed for raising your own is sown from 18 March to 15 July. Within 15 km of Grand Junction OpenStreetMap lists 5 garden centres, 1 farm-supply shop, 1 market and 1 farm shop (collected 28 October 2026).

Bookcliff Gardens — garden centre
26 Road 755, 81506 Grand Junction · 3 km
West Elk Supply — farm supply
Northgate Drive 599, 81505 Grand Junction · 2 km
Jim's Lawnmower Shop — market
Palmer Street 1825, 81503 Grand Junction · 5 km
Willow Bend Farm — farm shop
8 km

Each window starts on the Greenly calendar date and ends on the last day that still leaves the crop’s days to harvest (from its card) before the average first autumn frost, plus six weeks of picking for crops harvested over weeks (tomatoes, peppers, aubergines, cucumbers, courgettes, pumpkins, watermelons, beans) — our rule; earlier in the window is safer.

Questions